T-18 tank

MS-1 light tank
MS-1 at the Moscow museum of Armed Forces
Type	Light tank
Place of origin	Soviet Union
Production history
Produced	1928-1931
Specifications
Weight	5.9 tonnes
Length	4.38 m (14 ft 4 in)
Width	1.76 m (5 ft 9 in)
Height	2.10 m (6 ft 11 in)
Crew	2
Armor	6-16 mm
Main armament	37mm Model 28
Secondary armament	2 Fedorov Avtomat machine guns
Engine	T-18 35 hp (26 kW)
Power/weight	5.9 hp/tonne
Suspension	vertically sprung
Operational range	50 km (31 mi)
Speed	17 km/h (10 mph)

The T-18 light tank (also called MS-1, Russian: малый сопровождения, первый, tr. Maliy Soprovozhdeniya, Perviy, "First Small [Vehicle for] Support") was the first Soviet-designed tank. Produced from 1928 to 1931, it was based on the Renault FT, with the addition of a vertically sprung suspension.

The T-18 and its derivatives were essentially unsuccessful designs, but they gave Soviet industry its first experiences in designing armoured vehicles, and in the meantime a number of foreign tank designs were available for production.

A "Tank Bureau" was formed in May 1924 for the development of Soviet tanks. A specification was issued for a 3-tonne two-man light tank capable of 7.5 mph (12.1 km/h). It would be protected by 16 mm of armour and equipped with a 37 mm (1.5 in) gun. By 1925 the allowable weight had increased to 5 tonnes.

The tank was designed by Professor V. Zaslavsky at a new Tank Bureau set up under the Central Directorate of Military Industries. The 35-horsepower truck engine (a copy of the Italian FIAT 15 ter) was supplied by the Moscow AMO Factory, and the gun was a modified copy of the French 37 mm Puteaux SA 18 cannon. The sprung suspension which would allow a tank to travel faster over rough ground was the biggest improvement over the Renault. A prototype called the T-16 was tested in June 1927.

The T-16 was deemed a failure, as it had problems with its transmission failing too often and its inability to cross trenches more than 1.5 m wide. The T-16's maneuverability was only marginally better than that of the Renault. Meanwhile, the КБ ОАТ drew up plans for an improved version of the T-16 which was accepted for production in July as the T-18, with the tank additionally noted as an MS-1 ("Support vehicle, small, type 1").

The T-18's chassis and suspension was improved from the T-16 by the addition of an extra support roller and an independent vertical spring suspension. The 300 mm track of the T-16 was transferred over to the T-18, with some improvements. The engine, a vertical, four-cylinder MS engine, was designed and improved upon by Alexander Mikulin. The engine was capable of a maximum of 35 horsepower. The MS engine was combined with the PSC transmission in one unit rather than being in two separate housings. The PSC transmission gave the tank four forward speeds and one reverse speed. The engine-transmission compartment in the back let air in via holes drilled in the rear plate. This improved protection, but also led to the engine overheating. Electrical equipment included a 6-volt battery, magneto and dynamo, which fed the lamp, horn, rear light, light distribution panel and two portable lamps.